recurve the distributor

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concrete52

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what does it mean to have the distributer recurved - have a 225 slant 6 that will be rebuilt properly - looking at not a high performance ride though a good efficient working car - looking at the two barrel super 6 at the moment -
 
I don't think you can buy them for a slant, but "FBO ignition" has a kit that makes it easy to do a V8. Called a limiter plate. I don't know how good they work

Otherwise, the "old school" was to weld up and then file up the slots in the advance so they could not move as far, and use lighter springs to make it advance quicker. Here's an article, a good one

http://www.moparmusclemagazine.com/techarticles/engine/mopp_0301_mopar_electronic_ignition_system/


One thing you need to be aware of is "crank" and "distributor" degrees. In all the books, advance RPM and degrees are stated in "distributor" degrees which is HALF of crank degrees. In that article, they point out a "15" stamped on the advance of a V8 unit. This is THIRTY degrees at the crank.
 
Recurving the distributor means changing the mechanical advance that moves the ignition timing as the engine accelerates. The mechanical advance is changed by the weights under the rotor on the plate which are thrust outwards as the engine speed increases. These weights rotate the plate which advances or retards the rotor 'bug' with engine speed changing the 'curve' of the timing as it would be observed on a plotted chart.
The curve is controlled by the spring tension on the counterweights (and by the vacuum advance on the side of the distributor). By changing the spring tension you change the curve to better fit your desired engine performance. Factory distributors are set to maximize performance verses economy. You can change the springs and the initial timing to either get higher performance or better economy.

I think I explained this right.

Check the guys out discussing the distributor testing machines - they have lots of fun doing this stuff.

www.forabodiesonly.com/mopar/showthread.php?t=216539
 
Uh, ahem LOL. That's my old Allen. No, LOL, I still don't have it back together
 
Bcudamatt said:
... Factory distributors are set to maximize performance verses economy. You can change the springs and the initial timing to either get higher performance or better economy.
Click to expand...

I would rather say;
"Factory distributors are set to a safe compromise of engine durability, performance, economy, to be used in a wide range of temperature and outside airpressure differences (think sea-level and mountain areas)."

So there's more power to be had if one is willing to optimise the advance for your particular situation.
 
I have a great article from HP Mopar magazine - March 96 - Throwing a Curve - by Rick Chinoski - I can scan it if you like.
 
BigBlockMopar said:
I would rather say;
"Factory distributors are set to a safe compromise of engine durability, performance, economy, to be used in a wide range of temperature and outside airpressure differences (think sea-level and mountain areas)."

So there's more power to be had if one is willing to optimise the advance for your particular situation.
Click to expand...

In my opinion, you are somewhat correct, except and especially the later the year. By 72 or 73 or so, and onwards, the "smog controls" requirements pretty much overshadowed ANY concern for either performance, driveability, or even durability, and most certainly economy. I well remember those days, of "hot dieseling on shutdown" really poor starting on cold days, and dying or nearing dying when trying to get going on a cold winter day. It wasn't all "curve" of course, it was the whole engine package.
 
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